The judge held that Mr Hain failed to take into account the important and relevant consideration that the independence of such an inquiry was compromised by Section 14 of the 2005 Act giving a Minister power to terminate the inquiry at any time.

He said Mr Hain was wrongly advised that an equivalent power existed under the Prisons Act.

Mr Justice Deeny said that as the decision-maker, Mr Hain did not direct himself nor did he have called to his attention, the “novel and unrestricted power given to him and his successors as Ministers in a Northern Ireland administration.

“In saying that I make it clear that my criticism of the decision does not involve a personal criticism of the decision-maker,” he said.

“There was no question of bad faith here. He ought to have been advised, at the least, that there was a seriously contentious issue relating to the powers under Section 14.”